The ATK is a new vehicle in Fortnite season 5, an ‘All Terrain Kart’ As it is called. It can drive 25 miles per hour, and can generate some wicked speed boosts by using a drift ability. When using this ability, you can bank around corners, do doughnuts, and during the use of this ability, you can gain a speed boost that activates when you release it the drift. I do not currently know the maximum speed you can go, but I know that you can go at least 34 miles per hour, totaling in a 9 mile per hour speed boost!
The Kart is pretty fun, and if you can’t get on and play with it right now, or if you have and you still can’t get enough, here is a video of me messing around with the ATK.